Volcanic Eruption of the Day: Rapture back on?: Grímsvötn -- Iceland's most active volcano -- has just blown its top, sending a plume of ash 18,000-feet in the air, and triggering some 50 small earthquakes.

The Grímsvötn volcano's last eruption in 2004 lasted about a week.

Despite its dramatic appearance, experts don't expect a repeat of the air travel disruption that occurred in the af